What causes such variation in vintage condition?

[AS1]

I'd love to hear thoughts from my fellow vintage lovers as to what sort of factors, over the years, causes such variation in vintage pieces.

With the cases it's easy. If someone was careless, it's easy to see how the case and bracelet get dinged up.

The dials and hands have always intrigued me. We see watches from identical years with lume completely flaked off, scratches on the dial, stuff like that; yet others are pristine. In extreme cases I can see how water damage or careless servicing could cause those issues, but it doesn't seem possible to me that those sorts of things can account for the wide variation we see in condition.

Is it possible, for example, that two watches that left the factory at the same time were almost destined for different lives based on how paint was applied, lume was applied, stuff like that?

Would love to hear thoughts!